Over the last 250 years, our skulls have morphed in dangerous and troubling ways.
Nasal passages and jaws are narrowing, overbites are becoming more extreme, palates are rising, skulls are shrinking. The result is less face to fit everything into, meaning crowded dentition, breathing problems, and potentially insufficient space for growing brains. It could even be a root cause of elevating asthma rates, joint pain (particularly in the young), and allergies, whilst sleep disruption caused by narrow air spaces is already well documented at causing anxiety, depression, and behavioural disorders in people of any age.
Narrowing of facial features, in particular, seems linked with industrialisation; less-industrialised nations suffer from these issues less and the anthropological record show these conditions to be incredibly rare throughout human history. From about 250 years ago, morphological changes away from a consistently "broad, straight, wide" skull shape seems to have accelerated. One possible reason is the sudden introduction of bottle-feeding and soft "baby" food that may cause our chewing muscles to underdevelop. Environmental pollutants are a second potential factor (obviously).
The impact is most serious in children. Studies cited have shown links with sleep issues in young kids can reduce their functional abilities by the equivalent of two years (!) and result in lower average lifetime earnings. It increases mood swings and makes kids cranky, less able to focus, retain information, or be creative. It's also a key risk factor in childhood obesity.
Parents know sleep is important, but they rarely realize how proper sleep relies on a wide dental arch, tongue on the roof of the mouth, and long lower jaw.
Treatment using centuries-old techniques has positive results:
Within a month, Micah’s sleeping improved and his behavior transformed. Previously, he cried at doctor’s appointments, balked at going to school, acted cranky, and hid behind his mom around guests. Now, he smiles freely and runs up to his grandparents for hugs.